Field of the Invention
The present invention is related to image display and more particularly, a method and an apparatus for minimizing a black offset in a multi-projection environment.
Discussion of the Related Art
The projector is not able to project black color properly, that is, it projects black color with a certain intensity of gray color (for example, (R, G, B) =(25, 25, 25)), not pure black ((R, G, B) =(0, 0, 0)) on a screen.
For this reason, when a dark image which is close to pure black of high definition such as a panorama with a multi-projector is projected on a large screen, a black offset phenomenon occurs on an overlapped region.
FIG. 1 illustrates an example of occurrence of the black offset on multi-projection according to a prior art. FIG. 1(a) illustrates an example of the black offset occurred on a screen when the multi-projection of a panorama image is conducted. And FIG. 1(b) illustrates the result of an intensity plot obtained by capturing the image of FIG. 1(a).
The black offset phenomenon shown on the overlapped region as illustrated in FIG. 1 occurs in most of projectors, and becomes a fundamental problem that projecting a seamless image is not available in the multi-projection. Mostly, when the multi-projection is performed on a large screen in such as exhibition centers, the contents close to black are not projected due to such a problem.
Accordingly, a technique that makes it possible to implement a seamless projection by minimizing the black offset in the multi-projection environment is needed in the field.